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Java > Open Source Codes > org > apache > commons > jxpath > ri > compiler > CoreOperationCompare


1 /*
2  * Copyright 2002-2004 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.jxpath.ri.compiler;
17
18 import java.util.Collection JavaDoc;
19 import java.util.HashSet JavaDoc;
20 import java.util.Iterator JavaDoc;
21
22 import org.apache.commons.jxpath.Pointer;
23 import org.apache.commons.jxpath.ri.EvalContext;
24 import org.apache.commons.jxpath.ri.InfoSetUtil;
25 import org.apache.commons.jxpath.ri.axes.InitialContext;
26 import org.apache.commons.jxpath.ri.axes.SelfContext;
27
28 /**
29  * Common superclass for the implementations of Expression for the operations
30  * "=" and "!=".
31  *
32  * @author Dmitri Plotnikov
33  * @version $Revision: 1.3 $ $Date: 2004/02/29 14:17:38 $
34  */
35 public abstract class CoreOperationCompare extends CoreOperation {
36
37     public CoreOperationCompare(Expression arg1, Expression arg2) {
38         super(new Expression[] { arg1, arg2 });
39     }
40
41     /**
42      * Compares two values
43      */
44     protected boolean equal(
45         EvalContext context,
46         Expression left,
47         Expression right)
48     {
49         Object JavaDoc l = left.compute(context);
50         Object JavaDoc r = right.compute(context);
51
52 // System.err.println("COMPARING: " +
53 // (l == null ? "null" : l.getClass().getName()) + " " +
54 // (r == null ? "null" : r.getClass().getName()));
55
56         if (l instanceof InitialContext || l instanceof SelfContext) {
57             l = ((EvalContext) l).getSingleNodePointer();
58         }
59
60         if (r instanceof InitialContext || r instanceof SelfContext) {
61             r = ((EvalContext) r).getSingleNodePointer();
62         }
63
64         if (l instanceof Collection JavaDoc) {
65             l = ((Collection JavaDoc) l).iterator();
66         }
67
68         if (r instanceof Collection JavaDoc) {
69             r = ((Collection JavaDoc) r).iterator();
70         }
71
72         if ((l instanceof Iterator JavaDoc) && !(r instanceof Iterator JavaDoc)) {
73             return contains((Iterator JavaDoc) l, r);
74         }
75         else if (!(l instanceof Iterator JavaDoc) && (r instanceof Iterator JavaDoc)) {
76             return contains((Iterator JavaDoc) r, l);
77         }
78         else if (l instanceof Iterator JavaDoc && r instanceof Iterator JavaDoc) {
79             return findMatch((Iterator JavaDoc) l, (Iterator JavaDoc) r);
80         }
81
82         return equal(l, r);
83     }
84
85     protected boolean contains(Iterator JavaDoc it, Object JavaDoc value) {
86         while (it.hasNext()) {
87             Object JavaDoc element = it.next();
88             if (equal(element, value)) {
89                 return true;
90             }
91         }
92         return false;
93     }
94
95     protected boolean findMatch(Iterator JavaDoc lit, Iterator JavaDoc rit) {
96         HashSet JavaDoc left = new HashSet JavaDoc();
97         while (lit.hasNext()) {
98             left.add(lit.next());
99         }
100         while (rit.hasNext()) {
101             if (contains(left.iterator(), rit.next())) {
102                 return true;
103             }
104         }
105         return false;
106     }
107
108     protected boolean equal(Object JavaDoc l, Object JavaDoc r) {
109         if (l instanceof Pointer && r instanceof Pointer) {
110             if (l.equals(r)) {
111                 return true;
112             }
113         }
114
115         if (l instanceof Pointer) {
116             l = ((Pointer) l).getValue();
117         }
118
119         if (r instanceof Pointer) {
120             r = ((Pointer) r).getValue();
121         }
122
123         if (l == r) {
124             return true;
125         }
126
127 // System.err.println("COMPARING VALUES: " + l + " " + r);
128 if (l instanceof Boolean JavaDoc || r instanceof Boolean JavaDoc) {
129             return (InfoSetUtil.booleanValue(l) == InfoSetUtil.booleanValue(r));
130         }
131         else if (l instanceof Number JavaDoc || r instanceof Number JavaDoc) {
132             return (InfoSetUtil.doubleValue(l) == InfoSetUtil.doubleValue(r));
133         }
134         else if (l instanceof String JavaDoc || r instanceof String JavaDoc) {
135             return (
136                 InfoSetUtil.stringValue(l).equals(InfoSetUtil.stringValue(r)));
137         }
138         else if (l == null) {
139             return r == null;
140         }
141         return l.equals(r);
142     }
143
144 }
145
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